Most of the time when I need to reference something using the word "laugh", my go-to preposition is "about". However, at times, "over" sounds much more adequate in day-to-day use.
The big question, then, is when do we prefer laugh over to laugh about? For instance, if you Google "laugh over", the following sentence example appears:
We had a quiet laugh over it.
There, for me at least, "about" would not be the suitable choice. Is there some rationale? Or is it a turn of phrase?